Added Rock-Paper-Scissors game script(Python)

[KomalSikchi]

What I added

• New Python script Python/rock_paper_scissors.py that implements a simple interactive Rock-Paper-Scissors game (user vs computer).
• Input validation, short forms allowed (r/p/s), and a replay/quit option.

How to run

1. Clone the repo
2. python Python/rock_paper_scissors.py

Notes

• Time complexity: O(n) per number of rounds (each round is constant work).
• Space complexity: O(1).